1,251 research outputs found

    Superconducting d-wave stripes in cuprates: Valence bond order coexisting with nodal quasiparticles

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    We point out that unidirectional bond-centered charge-density-wave states in cuprates involve electronic order in both s- and d-wave channels, with non-local Coulomb repulsion suppressing the s-wave component. The resulting bond-charge-density wave, coexisting with superconductivity, is compatible with recent photoemission and tunneling data and as well as neutron-scattering measurements, once long-range order is destroyed by slow fluctuations or glassy disorder. In particular, the real-space structure of d-wave stripes is consistent with the scanning-tunneling-microscopy measurements on both underdoped Bi2Sr2CaCu2O8+x and Ca2-xNaxCuO2Cl2 of Kohsaka et al. [Science 315, 1380 (2007), arXiv:cond-mat/0703309].Comment: 5 pages, 3 figs, (v2) final version to be published in PR

    Literature Study on Factors Influencing the Market Acceptance of PSS

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    AbstractProduct-Service Systems (PSS) as an integration of product and service elements in one market offer promise amongst others better fulfillment of customer demand, quicker innovation, differentiation from competitors and sustainability. However in the industrial practice there are major challenges in successfully offering these PSS. One of these challenges is to gain market acceptance for PSS. Whereas benefits for providers and customers have been widely discussed in literature, going beyond these statements and analyzing factors on the market acceptance of PSS is hardly discussed. The paper gives the theoretical foundations for a model explaining an integrated set of factors for and against the market acceptance of PSS in B2B environments

    A Machine Learning-Based Raman Spectroscopic Assay for the Identification of Burkholderia mallei and Related Species

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    Burkholderia (B.) mallei, the causative agent of glanders, and B. pseudomallei, the causative agent of melioidosis in humans and animals, are genetically closely related. The high infectious potential of both organisms, their serological cross-reactivity, and similar clinical symptoms in human and animals make the differentiation from each other and other Burkholderia species challenging. The increased resistance against many antibiotics implies the need for fast and robust identification methods. The use of Raman microspectroscopy in microbial diagnostic has the potential for rapid and reliable identification. Single bacterial cells are directly probed and a broad range of phenotypic information is recorded, which is subsequently analyzed by machine learning methods. Burkholderia were handled under biosafety level 1 (BSL 1) conditions after heat inactivation. The clusters of the spectral phenotypes and the diagnostic relevance of the Burkholderia spp. were considered for an advanced hierarchical machine learning approach. The strain panel for training involved 12 B. mallei, 13 B. pseudomallei and 11 other Burkholderia spp. type strains. The combination of top- and sub-level classifier identified the mallei-complex with high sensitivities (>95%). The reliable identification of unknown B. mallei and B. pseudomallei strains highlighted the robustness of the machine learning-based Raman spectroscopic assay

    Polaronic behavior of undoped high-Tc cuprates

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    We present angle-resolved photoemission spectroscopy (ARPES) data on undoped La2CuO4, indicating polaronic coupling between bosons and charge carriers. Using a shell model, we calculate the electron-phonon coupling and find that it is strong enough to give polarons. We develop an efficient method for calculating ARPES spectra in undoped systems. Using the calculated couplings, we find the width of the phonon side band in good agreement with experiment. We analyze reasons for the observed dependence of the width on the binding energy.Comment: 4 pages, RevTeX, 5 eps figures, more material available at http://www.fkf.mpg.de/andersen/phonons

    Is Neolithic land use correlated with demography? An evaluation of pollen-derived land cover and radiocarbon-inferred demographic change from Central Europe

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    The transformation of natural landscapes in Middle Europe began in the Neolithic as a result of the introduction of food-producing economies. This paper examines the relation between land-cover and demographic change in a regionally restricted case study. The study area is the Western Lake Constance area which has very detailed palynological as well as archaeological records. We compare land-cover change derived from nine pollen records using a pseudo-biomisation approach with 14C date probability density functions from archaeological sites which serve as a demographic proxy. We chose the Lake Constance area as a regional example where the pollen signal integrates a larger spatial pattern. The land-cover reconstructions for this region show first notable impacts at the Middle to Young Neolithic transition. The beginning of the Bronze Age is characterised by increases of arable land and pasture/meadow, whereas the deciduous woodland decreases dramatically. Changes in the land-cover classes show a correlation with the 14C density curve: the correlation is best with secondary woodland in the Young Neolithic which reflects the lake shore settlement dynamics. In the Early Bronze Age, the radiocarbon density correlates with open land-cover classes, such as pasture, meadow and arable land, reflecting a change in the land-use strategy. The close overall correspondence between the two archives implies that population dynamics and land-cover change were intrinsically linked. We therefore see human impact as a key driver for vegetation change in the Neolithic. Climate might have an influence on vegetation development, but the changes caused by human land use are clearly detectable from Neolithic times, at least in these densely settled, mid-altitude landscapes

    Evidence of fNIRS-based prefrontal cortex hypoactivity in obesity and binge-eating disorder

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    Obesity (OB) and associated binge-eating disorder (BED) show increased impulsivity and emotional dysregulation. Albeit well-established in neuropsychiatric research, functional near-infrared spectroscopy (fNIRS) has rarely been used to study OB and BED. Here, we investigated fNIRS-based food-specific brain signalling, its association with impulsivity and emotional dysregulation, and the temporal variability in individuals with OB with and without BED compared to an age- and sex-stratified normal weight (NW) group. Prefrontal cortex (PFC) responses were recorded in individuals with OB (n = 15), OB + BED (n = 13), and NW (n = 12) in a passive viewing and a response inhibition task. Impulsivity and emotional dysregulation were self-reported; anthropometrics were objectively measured. The OB and NW groups were measured twice 7 days apart. Relative to the NW group, the OB and OB + BED groups showed PFC hyporesponsivity across tasks, whereas there were few significant differences between the OB and OB + BED groups. Greater levels of impulsivity were significantly associated with stronger PFC responses, while more emotional dysregulation was significantly associated with lower PFC responses. Temporal differences were found in the left orbitofrontal cortex responses, yet in opposite directions in the OB and NW groups. This study demonstrated diminished fNIRS-based PFC responses across OB phenotypes relative to a NW group. The association between impulsivity, emotional dysregulation, and PFC hypoactivity supports the assumption that BED constitutes a specific OB phenotype

    Finite-Temperature Transition in the Spin-Dimer Antiferromagnet BaCuSi2O6

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    We consider a classical XY-like Hamiltonian on a body-centered tetragonal lattice, focusing on the role of interlayer frustration. A three-dimensional (3D) ordered phase is realized via thermal fluctuations, breaking the mirror-image reflection symmetry in addition to the XY symmetry. A heuristic field-theoretical model of the transition has a decoupled fixed point in the 3D XY universality, and our Monte Carlo simulation suggests that there is such a temperature region where long-wavelength fluctuations can be described by this fixed point. However, it is shown using scaling arguments that the decoupled fixed point is unstable against a fluctuation-induced biquadratic interaction, indicating that a crossover to nontrivial critical phenomena with different exponents appears as one approaches the critical point beyond the transient temperature region. This new scenario clearly contradicts the previous notion of the 3D XY universality.Comment: 16 pages, 7 figure

    Die Rolle des öffentlich-rechtlichen Rundfunks im Zeitalter von TikTok: ökonomische Anmerkungen

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    Die Digitalisierung hat Medienmärkte grundlegend verändert: Statt begrenzten Funkfrequenzen und festen Programm, werden Medieninhalte über unterschiedlichste Kanäle verteilt, erstellt, geteilt und diskutiert. Digitale Plattformen haben den Konsum grundlegend verändert und ermöglichen es Nutzer außerdem, einfach und schnell Medieninhalte zu erstellen. So wird nicht nur die Linearität des Programms aufgelöst, auch die Grenze zwischen Produzenten und Konsument verschwindet zunehmend, außerdem kuratieren wenige Plattformen welche Inhalte wie angezeigt werden. Vor diesem Hintergrund analysiert dieser Beitrag die Rolle des öffentlich-rechtlichen Rundfunks und wirft die Frage auf, welche Rolle er in einer digitalen Welt spielen müsste. Zum einen wäre die Einführung eines öffentlich-rechtlichen Rundfunks in seiner heutigen Form, ökonomisch nicht zu rechtfertigen. Zum anderen kann der öffentlich-rechtliche Rundfunk viele Herausforderungen, die durch digitale Plattformen wie TikTok entstehen nicht ausreichend adressieren. Um einen öffentlich-rechtlichen Rundfunk für das digitale Zeitalter zu entwerfen, müssten erst die ökonomischen Herausforderungen benannt und analysiert werden, umso zukunftsträchtige Lösungen entwickeln zu können

    Low-cost multipurpose sensor network integrated with iot and webgis for fire safety concerns

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    Fire emergencies cause severe damage to Brazilian federal universities. An appropriate and efficient tool to prevent or detect such events early is multisensory networks from the Internet of Things (IoT). In this study, we present the stages of development of a WebGIS system which integrates the IoT that allows the detection and helps manage such incidents. The approach consists of a network of multipurpose sensors that can identify different sources of fire hazards. If a potential source is registered, information about environmental conditions is transmitted in real-time to the system. Depending on the severity level, an alert is issued to WebGIS. Location is represented on a map. The entire system consists of single-board devices. Software components are based on open-source tools. The whole network only needs little power and, therefore, theoretically, could be carried out as an autonomous system powered by batteries. The entire system has been tested with flame, temperature, gas, smoke, and humidity sensors. The experiments allowed us to show its potential, formulate recommendations and indications for future studies
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